Didn't know if this would work, but thought I'd give it a try anyway. The idea is to coat some leaves (or other vegetation as the mood strikes) with varnish in preparation for attaching them to slabs for "effect". After they are coated and applied to the slabs, they'll be covered with more coats of varnish to really seal them in.
The first effort was to use an artist's brush, varnish one side of the leaf and then the other. I won't even go into what an abject failure that was. Well, ok, maybe I will. Brushing one side at a time and letting it dry before being able to do the other side of the leaf had a tendency to make it curl - and I do mean curl. After I brushed the other side and let it completely dry, I had to put the leaf between wax paper and apply weight for a coupla days before it was flat enough again to even consider using it on a flat surface. There just had to be a better way.
The second effort, after my brain fart, was to "hang" the leaves from a rod using a loop of bale binder twine and a bobby pin (clothes pins will surely work better, but I didn't have any when I did this - so, off to the store to get some).
Still wasn't sure about whether or not doing both sides at once would prevent curling, but was very pleasantly surprised at how the leaves maintained their natural shape. The can you see in the photos is the spray varnish I used. It's a Minwax gloss water based polyurethane. If the leaves maintain their green color like I hope they will, I'll also be asking relatives out east to send me bags full of maple, oak, and walnut leaves this fall after they turn color for Autumn.
Once I apply these aspen leaves to some of my pieces, I'll post photos of them on my Facebook page: https://www.facebook.com/pages/Dead-Wood-Renaissance/361417090585685?ref=hl